Lubricant composition containing 3-amidopyridine corrosion inhibitor

ABSTRACT

Lubricant compositions containing, in an amount sufficient to inhibit metal corrosion, an amidopyridine obtained by reacting an aminopyridine and oleic acid.

United States Patent [1 1 Gemmill, Jr.

[451 May 20, 1975 1 LUBRICANT COMPOSITION CONTAINING 3-AMIDOPYRIDINE CORROSION INHIBITOR [75] Inventor: Robert M. Gemmill, Jr., Pitman,

[73] Assignee: Mobil Oil Corporation, New York,

[22] Filed: July 6, 1973 [21] App]. No.: 377,002

[52] US. Cl 252/51.5 A; 252/392; 252/403 [51] Int. Cl ClOm 1/32 [58] Field of Search 252/51.5 A, 392, 403

[56] References Cited UNITED STATES PATENTS 3,303,131 2/1967 Low et al 252/51.S A X Hotten 252/5l.5 A X Davies et a1, 252/52 R Primary ExaminerDelbert E. Gantz Assistant ExaminerAndrew H. Metz Attorney, Agent, or FirmChar1es A. Huggett; Raymond W. Barclay; Benjamin 1. Kaufman 7 Claims, No Drawings LUBRICANT COMPOSITION CONTAINING 3-AMIDOPYRIDINE CORROSION INHIBITOR BACKGROUND OF THE INVENTION 1. Field of the Invention.

This invention relates to lubricant compositions and, in one of its aspects, relates more particularly to lubricant compositions having improved properties for prevention of metal corrosion in performing their functions. Still more particularly, in this aspect, the invention relates to lubricant compositions in the form of lubricating oils and greases containing additives effective for inhibiting metal corrosion.

2. Description of the Prior Art.

The prior art has long recognized that lubricants, in the form of lubricating oils and greases, apart from performing their intended functions of lubricating metal parts, also exhibit the characteristic of permitting corrosion of metal surfaces with which they may come into contact. In order to control such corrosion, various additives have been suggested. Some of these additives have not proved to afford any appreciable improvement, while others, although more effective, have been found to be too costly.

SUMMARY OF THE INVENTION In accordance with the present invention, lubricant compositions are provided containing, in an amount sufficient to inhibit metal corrosion, an amidopyridine obtained by reacting an aminopyridine and oleic acid. These reaction product additives, as more fully hereinafter described, are outstandingly effective in inhibiting the metal corrosion properties of lubricants and are also economical to use.

The aforementioned amidopyridine may be incorporated in any lubricating media which may comprise liquid hydrocarbon oils, in the form of either a mineral oil or a synthetic oil, or in the form of a grease in which any of the aforementioned oils are employed as a vehicle. In general, mineral oils, employed as the lubricant, or grease vehicle, may be of any suitable lubricating viscosity range, as, for example, from about 45 SSU at 100 F. to about 6,000 SSU at 100 F., and, preferably, from about 50 to about 250 SSU at 210 F. These oils may have viscosity indexes varying from below zero to about 100 or higher. Viscosity indexes from about 70 to about 95 are preferred. The average molecular weights of these oils may range from about 250 to about 800. Where the lubricant is to be employed in the form ofa grease, the lubricating oil is generally employed in an amount sufficient to balance the total grease composition, after accounting for the desired quantity of the thickening agent, and other additive components to be included in the grease formulation.

In instances where synthetic oils, or synthetic oils employed as the vehicle for the grease, are desired in preference to mineral oils, or in combination therewith, various compounds of this type may be successfully utilized. Typical synthetic vehicles include polyisobutylene, polybutenes, hydrogenated polydecenes, polypropylene glycol, polyethylene glycol, trimethylol propane esters, neopentyl and pentaerythritol esters, di(2-ethyl hexyl) seba'cate. di(2-ethyl hexyl) adipate, dibutyl phthalate, fluorocarbons, silicate esters, silanes, esters of phosphorous-containing acids. liquid ureas, ferrocene derivatives, hydrogenated mineral oils, chain-type polyphenyls, siloxanes and silicones (polysiloxanes),

alkyl-substituted diphenyl ethers typified by a butylsubstituted bis (p-phenoxy phenyl) ether, phenoxy phenylethers, etc.

The aminopyridine and the oleic acid are reacted in a mol ratio of from 1:1 to about 1:2. In general, the reaction may be carried out at a temperature from about C. to about 210 C., and preferably at a temperature from about 160 C. to about 200 C. The amidopyridine may be incorporated in the lubricant in any amount effective for inhibiting metal corrosion. In many instances, the reaction product may be incorporated in the lubricant in an amount from about 0.1 to about 5%, and, preferably, in an amount from about 0.3 to about 3%, by weight, of the total lubricant composition.

The reaction between the aminopyridine and oleic acid may be illustrated as follows:

/ M1 +oleic acid @NH (H 2 6 DESCRIPTION OF SPECIFIC EMBODIMENTS The following examples and comparative data will serve to illustrate the novel metal corrosion inhibiting amidopyridines of the present invention, the method for their preparation and their'utility in lubricating media as antirust agents.

EXAMPLE 1PREPARATION OF 4-AMIDOPYRIDINE A mixture of 141.3 grams (0.50 mole) of oleic acid and 23.5 grams (0.25 mole) of 4-aminopyridine was reacted in the presence of 100 ml. xylene at l50-190 C. for about 38 hours to form a dark, red-amber colored, liquid product. The theoretical 4.5 grams (0.25 mole) of water was evolved by azeotropic distillation with the xylene.

The xylene and excess oleic acid were removed by vacuum distillation. The resulting product was pure 4- amidopyridine as characterized by gas chromatography and infrared spectral analysis.

EXAMPLE 2PREPARATION OF Z-AMIDOPYRIDINE A mixture of 141.3 grams (0.50 mole) of oleic acid and 23.5 grams (0.25 mole) of 2-aminopyridine was reacted in the presence of 100 ml xylene at 160170 C. for about 25 hours to form a dark, red-amber colored, liquid product. The theoretical 4.5 grams (0.25 mole) of water was evolved by azeotropic distillation with the xylene.

The xylene and excess oleic acid were removed by vacuum distillation. The resulting product was pure 2- amidopyridine as characterized by gas chromatography and infrared spectral analysis.

EXAMPLE 3PREPARATION OF 3-AM1DOPYRIDINE A mixture of 141.3 grams (0.50 mole) of oleic acid and 23.5 grams (0.25 mole) of 3-aminopyridine was reacted in the presence of 100 ml. xylene at -l85 C. for about 29 hours to form a dark, red-amber colored,

liquid product. The theoretical 4.5 grams (0.25 mole) of water was evolved by azeotropic distillation with the xylene.

The xylene and excess oleic acid were removed by vacuum distillation. The resulting product was pure 3- amidopyridine as characterized by gas chromatography and infrared analysis.

HUMIDITY CHAMBER RUST TESTS This is a general purpose and severe rust test. It utilizes a humidity chamber operated at 120 F. and 979 8% Relative Humidity with an air circulation rate of 150 cubic feet per minute. The test panels are 2 inches X 4 inches one-eighth inch polished steel plates of SAE 1010 steel of a 10 micron finish.

The test is performed by first cleaning a new panel in naphtha, absolute methanol and xylene in that order. The air dried panel is then dipped in a test formulation for 1 minute and then drip-dried for 2 hours prior to insertion into the chamber. The panels are suspended in a vertical position within the chamber and can be continuously monitored through the glass dome of the chamber.

The severity of the test can be judged by the rapid rusting rate (1 hour) of a panel coated only with a solvent-refined Mid-Continent SAE. 30 oil base stock, compared to complete rust inhibition for periods up to 5 days when utilizing a rust inhibitor in concentrations of 2 and 4.0% in the same oil.

The following data indicate the formulations tested and the ratings show the number of days to achieve the first indication of rust and the degree of rust at that time. The degree of rust is given since some antirust agents will allow only a gradual rusting rate while some allow a sudden, catastrophic rusting rate after their inhibiting ability is depleted.

amount of a lubricating oil or grease containing, in an amount sufficient to inhibit metal corrosion, a 3- amidopyridine having the structure:

0 ll (bu-c (on )7CH W H CH3 (CH2 70H 2. A composition as defined in claim 1 wherein said lubricant comprises a mineral oil-based composition.

3. A composition as defined in claim 1 wherein said lubricant comprises a synthetic oil-based composition.

4. A composition as defined in claim 1 wherein said lubricant comprises an oil of lubricating viscosity in the range from about SSU at 100 F. to about 6,000 SSU at 100 F.

5. A composition as defined in claim 1 wherein said lubricant comprises an oil of lubricating viscosity in the range from about SSU at 210 F. to about 250 SSU at 210 F. r

6. A composition as defined in claim 1 wherein said amidopyridine is present in an amount from about 0.l

to about 5%, by weight.

Additive Form ulation Days to first rust- Conc. Wt.% rating at that time S-Light, S-Moderate, 6-Trace 3-Trace, S-Heavy, 7-Moderate test.

The comparative data of the foregoing humidity 'TPSA is tetrapropenylsuccinic anhydridc known to be an effective rust inhibitor and used as a reference in this 7. A composition as defined in claim 1 wherein said chamber tests illustrate the efficacy of the novel amidopyridine is present in an amount from about 0.3

amidopyridines of the present invention in inhibiting metal corrosion.

to about 3%, by weight. 

1. A LUBRICATING COMPOSITION COMPRISING A MAJOR AMOUNT OF A LUBRICATING OIL OR GREASE CONTAINING, IN AN AMOUNT SUFFICIENT TO INHIBIT METAL CORROSION, A 3-AMIDOPYRIDINE HAVING THE STRUCTURE:
 2. A composition as defined in claim 1 wherein said lubricant comprises a mineral oil-based composition.
 3. A composition as defined in claim 1 wherein said lubricant comprises a synthetic oil-based composition.
 4. A composition as defined in claim 1 wherein said lubricant comprises an oil of lubricating viscosity in the range from about 45 SSU at 100* F. to about 6,000 SSU at 100* F.
 5. A composition as defined in claim 1 wherein said lubricant comprises an oil of lubricating viscosity in the range from about 50 SSU at 210* F. to about 250 SSU at 210* F.
 6. A composition as defined in claim 1 wherein said amidopyridine is present in an amount from about 0.1 to about 5%, by weight.
 7. A composition as defined in claim 1 wherein said amidopyridine is present in an amount from about 0.3 to about 3%, by weight. 